% 创建时间：2025-06-21 23:28:39
% 作者：兪馳
function E = sinm1(A)
    E = A;
    F = A;
    k = 0;
    while norm(E + F - E, 1) > 0
        F = -A^2 * F / (2 * (k + 3)) / (2 * k + 2);
        E = E + F;
        k = k + 1;
    end
end